In Automated Protection Switching (APS) schemes, a protection system including a single protection card provides protection for a plurality (i.e., N) of protected cards. In the case of a failed protected card, a protection switch requires that the protection card be downloaded with service data (e.g., call data) of the failed protected card before the protection card is fully brought into service. Downloading such service data can take up to as much as a few minutes or more depending on the amount of service data.
In the case of a fault, it is not usually known which one of the plurality of protected cards will require replacement. Therefore, it is not possible to download the service data to the protection card before a protection switch occurs. Consequently, services supported by the failed protected card will be adversely affected while the service data is being downloaded to the protection card.
During upgrade and maintenance of one of a plurality of the protected cards, the protection card may be used to back up the protected card being serviced. During such upgrade or service, a subscriber (i.e., a customer) will typically be adversely affected (e.g., by a disruption in service) for as much as several minutes as the protection card is downloaded with service data from the protected card being upgraded or maintained. Furthermore, during upgrade and maintenance, it is generally known which one of the protected cards will be replaced temporarily by the protection card. However, in conventional APS implementations, such knowledge of which one of the protected cards will be replaced temporarily by the protection card is not used to minimize the adverse effects associated with a service-affecting period resulting from the upgrade or maintenance. For voice calls, the service-affecting period during which the service data is being downloaded is often unacceptably long.
Conventional solutions for providing card protection exhibit one or more limitations. A first conventional solution for providing card protection is to overload one or more protection cards with connections for a plurality of protected cards. However, such an approach requires greatly increased memory capability to be provided on the protection cards. Limitations associated with the first conventional solution include the increased cost to implement it and the significant board space that it requires within a particular network apparatus. A second conventional solution is to use a 1:1 protection scheme such that a protection card is required for every protected card. Excessive cost is a key limitation of a 1:1 protection scheme.
Therefore, facilitating protection switching in a manner that overcomes limitations associated with conventional protection switching functionality is useful.
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